Epitaxial growth of 20 nm InAs and GaAs quantum dots on GaAs through block copolymer templated SiO2 masks

Alizadeh, Azar; Hays, David C.; Taylor, Seth T.; Keimel, Chris; Conway, Ken R.; Denault, Lauraine; Krishnan, Kasiraman; Watkins, V. H.; Neander, Rosalyn; Brown, Jay S.; Stintz, A.; Krishna, Sanjay; Blumin, M.; Saveliev, Igor; Ruda, Harry E.; Braunstein, Edit; Jones, C. E.

doi:10.1063/1.3082494

Cited by 13 publications

(10 citation statements)

References 32 publications

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“…Developments in nanotechnology allow the fabrication of densely packed, periodic structures [1][2][3][4]. Recently, ultra short period nanopore arrays and nanogratings have been obtained by block copolymer lithography [1,2]. Another method for nanograting fabrication is a multi-beam interference lithography.…”

Section: Introductionmentioning

confidence: 99%

Geometry-induced electron doping in periodic semiconductor nanostructures

Tavkhelidze

2014

Physica E: Low-dimensional Systems and Nanostructures

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Recently, new quantum features have been observed and studied in the area of nanostructured layers. Nanograting on the surface of the thin layer imposes additional boundary conditions on the electron wave function and induces G-doping or geometry doping. Gdoping is equivalent to donor doping from the point of view of the increase in electron concentration n. However, there are no ionized impurities. This preserves charge carrier scattering to the intrinsic semiconductor level and increases carrier mobility with respect to the donor-doped layer. G-doping involves electron confinement to the nanograting layer. Here, we investigate the system of multiple nanograting layers forming a series of hetero-or homojunctions. The system includes main and barrier layers. In the case of heterojunctions, both types of layers were G-doped. In the case of homojunctions, main layers were G-doped and barrier layers were donor-doped. In such systems, the dependence of n on layer geometry and material parameters was analysed. Si and GaAs homojunctions and GaAs/AlGaAs, Si/SiGe, GaInP/AlGAs, and InP/InAlAs heterojunctions were studied. G-doping levels of 10 18 -10 19 cm -3 were obtained in homojunctions and type II heterojunctions. High G-doping levels were attained only when the difference between band gap values was low.

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Section: Introductionmentioning

confidence: 99%

Geometry-induced electron doping in periodic semiconductor nanostructures

Tavkhelidze

2014

Physica E: Low-dimensional Systems and Nanostructures

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“…The need for higher performance and miniaturization of devices has raised considerable demand for small scale structures, pushing feature size and spatial resolutions down to sub‐50 nm length scales. Such patterns are of high interest for applications in photovoltaics,1 plasmonics,2 solid‐state lighting,3 sensors,4 energy storage,5 molecular separation,6 and patterned media 7. Lithography is a promising means of creating such structures with well‐defined feature size, periodicity, and with different combinations of technologically relevant materials and substrates.…”

Section: Introductionmentioning

confidence: 99%

Wafer‐Level Self‐Organized Copolymer Templates for Nanolithography with Sub‐50 nm Feature and Spatial Resolutions

Krishnamoorthy

Manipaddy

Yap

2011

Adv Funct Materials

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Robust lithographic templates, with sub-50 nm feature and spatial resolutions, that exhibit high patterning integrity across a full-wafer are demonstrated using self-organized copolymer reverse micelles on 100 mm Si wafers. A variation of less than 5% in the feature size and periodicity of polymeric templates across the entire wafer is achieved simply by controlling the spincoating process. Lithographic pattern transfer using these templates yields Si nanopillar arrays spanning the entire wafer surface and exhibiting high uniformity inherited from the original templates. The variation in geometric characteristics of the pillar arrays across the full-wafer surface is validated to be less than 5% using refl ectance spectroscopy. The physical basis of the change in refl ectance with respect to sub-10 nm variations in geometric parameters of pillar arrays is shown by theoretical modelling and simulations. Successful fabrication of highly durable TiO 2 masks for nanolithography with sub-50 nm feature width and spatial resolutions is achieved through highly controlled vapour phase processing of reverse micelle templates. This allows lithographic pattern-transfer of organic templates with a feature thickness and separation of less than 10 nm, which is otherwise not possible through other approaches reported in literature.

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“…After the semiconductor surface has been nanopatterned, various approaches have been used to form the QDs on either GaAs or InP substrates, such as nano-post etching of QW materials [72][73][74][75], selective growth using a dielectric mask [64,69,70,[76][77][78][79][80] or site-controlled growth [67,[81][82][83][84][85][86][87][88]. The formation of highly uniform nano-post (40 nm dia.)…”

Section: Qds Grown By Intentional Patterning-past Literaturementioning

confidence: 99%

Nanofabrication of III–V semiconductors employing diblock copolymer lithography

Kuech¹,

Mawst²

2010

J. Phys. D: Appl. Phys.

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To fully exploit the potential advantages of ideal quantum dots (QDs) (i.e. full 3D carrier confinement), elimination of the wetting layer and a uniform monomodal QD size distribution is needed. Nanopatterning with selective metalorganic chemical vapour deposition (MOCVD) QD growth has potential for achieving a higher degree of control over the QD formation, compared with the conventional Stranski–Krastanov (SK) self-assembly growth process. QD formation employing large surface area patterning prepared by dense nano-scale (20–30 nm diameter) diblock copolymer lithography is described. The resulting pattern consists of perpendicularly ordered cylindrical domain formed as part of a self-organizing diblock copolymer, such as polystyrene-block-poly(methylmethacrylate) (PS-b-PMMA). This pattern can be transferred to an underlying substrate or dielectric layer. Selective MOCVD growth of the QDs is achieved by employing the nanopatterned template mask. The resulting QD densities of 5 × 1010 cm−2 are comparable to densities achieved using the SK self-assembly growth mode. Nanopatterned growth yields a nearly monomodal QD size distribution. Variable temperature photoluminescence has been used to characterize the optical properties of capped InGaAs QDs on GaAs (λ ∼ 1.1 µm) and InP (λ ∼ 1.5 µm) substrates and preliminary results on the incorporation of such materials into diode laser structures are discussed. The extension of nanopatterned growth, beyond the pseudomorphic limit in the case of growth of strained-layer epitaxy, can lead to defect reduction and an improved morphology when compared with non-patterned growth.

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Epitaxial growth of 20 nm InAs and GaAs quantum dots on GaAs through block copolymer templated SiO2 masks

Cited by 13 publications

References 32 publications

Geometry-induced electron doping in periodic semiconductor nanostructures

Geometry-induced electron doping in periodic semiconductor nanostructures

Wafer‐Level Self‐Organized Copolymer Templates for Nanolithography with Sub‐50 nm Feature and Spatial Resolutions

Nanofabrication of III–V semiconductors employing diblock copolymer lithography

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